#include <stdio.h>
#include <unistd.h>
int main()
{
    char buf[512] = {0};
    printf("hhhhhhdangqianmulu:%s\n", getcwd(buf, sizeof(buf)));
    chdir("../");
    printf("xiugaihou:%s\n", getcwd(NULL, 0));
    printf("Hello world\n");
    return 0;
}

